Alditol ester derivatives of triclopyr, their preparation and herbicidal use thereof

ABSTRACT

Alditol ester derivatives of triclopyr are prepared and used as postemergent herbicides in cereal grain crop areas to kill and control various weeds.

This is a divisional of application Ser. No. 036,947, filed Apr. 10,1987, now U.S. Pat. No. 4,857,102.

BACKGROUND OF THE INVENTION

The compound 3,5,6-trichloro-2-pyridyloxy acetic acid, having the commonname triclopyr, is a commercial herbicide employed to kill and controlvarious weeds and grasses. Triclopyr is also known to cause phytotoxicdamage to cereal grains such as wheat, barley and rice when appliedpostemergently in a herbicidally effective amount upon weeds commonlyencountered in cereal grain crop areas. The compound is alsosufficiently volatile to warrant concern for susceptible valuable cropswhen applied to adjacent land.

It is therefore desirable to find ways to reduce the unwantedphytotoxicity of the compound thereby increasing its value for use inthe presence of cereal grain crops.

SUMMARY OF THE INVENTION

The present invention provides alditol ester derivative of triclopyrcorresponding to one of the following general formulae: ##STR1## whereinZ represents ##STR2## R¹ and R² are each independently any stericallycompatible combination of H, a C₁ -C₆ straight chain or branched alkylgroup, a C₃ -C₆ cycloalkyl group, or phenyl;

R¹ and R² taken together represent a divalent polymethylene group --CH₂--n, thereby forming a carbocyclic ring having N+1 carbon atoms whereinn is 3, 4, 5 or 6;

R³ is H or a group of the formula: ##STR3## R⁴ is H, CH₂ OH or a groupof formula B; and m is 1 or 2.

The term halogen is meant any of Br, Cl, F, or I, although Br and Cl arepreferred.

The compounds of the general formulae I, III and IV contain one or moreasymmetric carbon atoms, indicated as * in the formulae given above.

Thus, the compounds of the invention, having chiral groups, occur asoptical isomers and in some cases, they also exist in the form ofgeometrical isomers. Accordingly, the invention also provides for theindividual isomers as well as mixtures thereof and it should beunderstood that the written nomenclature and structural formulae shownin the present specification should be taken to include the individualisomers as well as mixtures thereof.

Compounds of the general formulae I, II, III and IV having substantiallylower volatility than triclopyr and having useful herbicidal activityagainst one or more significant broad leaf weeds such as fat hen(Chenopodium album) or red dead nettle (Lamium purpureum). The compoundsare thus useful in controlling such weeds in land adjacent valuablesusceptible crops.

Compounds of the general formulae I to IV wherein R¹ and R² are eachindependently H, CH₃, phenyl or phenyl substituted with one or twohalogen, lower alkyl, lower alkoxy, lower alkylthio, nitro and/ordialkylamino groups; m is 1 or 2: R³ is H or a group of formulae B andR⁴ is as defined above exhibit useful herbicidal activity against one ormore significant broad leaf weeds, such as fat hen (Chenopodium album)or red dead nettle (Lamium purpureum). In some instances the instantcompounds have herbicidal activity equal to or greater than triclopyr orits commercially available ester or sodium or amine salts, whileexhibiting excellent tolerance by cereal grains particularly wheat,barley and rice.

Of the compounds according to the invention, those prepared from theacetal of glycerol or from the acetonides of the pentitols, arabitol,adonitol and xylitol are of particular interest, more particularly thoseprepared from acetonides of arabitol and xylitol.

There should be mentioned especially those compounds in which R¹ and R²are the same or different and each represents H, CH₃ or phenyl. Moreespecially are those compounds in which R¹ and R² are each H or methylgroups, or in which R¹ is H and R² is phenyl. Preferably, R¹ and R² areeither identical, or else R¹ is hydrogen.

Examples of specific compounds having an excellent herbicidal actiontoward the weeds, fat hen and/or red dead nettle in addition toexcellent cereal grain tolerance at herbicidally effective dosage ratesfor the susceptible noxious weeds of the type described, include##STR4##

Compounds V, VI, VII and VIII are most preferred on account of theirherbicidal activity and broader spectrum.

Examples of compounds in accordance with the invention, which are not asselective as compounds to XIII above, but which nevertheless havesignificant herbicidal activity and low volatility are the following:##STR5##

It will be noted that certain of the above compounds, for example,compounds V, VII and XVI, appear from the structural formulae given tobe identical. These compounds, however, are different because theydiffer in their stereochemistry.

The compounds of the present invention may be prepared by the reactionof a compound of the formula ##STR6## wherein X is hydroxy, halogen orthe residue of C₁ -C₆ aliphatic alcohol with a compound of the formula

    HO-R.sup.5

wherein R⁵ is one of the general formulae ##STR7##

In particular, when the starting material is trichlopyr itself, i.e., Xis hydroxy, the reaction may preferably be carried out at roomtemperature in an inert polar solvent, such as tetrahydrofuran, oracetonitrile in the presence of a coupling agent such asN,N'-carbonyldiimidazole, or dicyclohexylcarbodiimide.

The solvent is preferably dried before use, for example, using amolecular sieve such as Aldrich type 3A or 4A.

The reaction of the acid halide of triclopyr (i.e., wherein X ishalogen) with the alditol derivative may be carried out at a temperatureof from about room temperature up to about 100° C. or more. The reactionis also carried out in a solvent such as acetonitrile, tetrahydrofuran,or dimethylsulfoxide and in the presence of an acid binding agent orscavenger (acid acceptor) such as dimethylamine, triethylamine,piperidine, pyridine, 4-dimethylaminopyridine, sodium carbonate, orpotassium carbonate to achieve the desired condensation. The reactionproduct may then be filtered to remove any salt produced, for example,the amine hydrochloride salt produced when the scavenger used is anamine.

The acid halide of triclopyr may be prepared by the reaction oftriclopyr with a suitable halogenating agent, such as SOCl₂ or POCl₃, inan inert aprotic solvent medium such as toluene, benzene or carbontetrachloride and under convention acid halide formation conditions toform the acid chloride or other acid halide.

When the starting material is an ester of triclopyr (i.e., X is theresidue of a C₁ -C₆ alcohol), the reaction is a transesterificationreaction, and is preferably carried out in an aprotic solvent medium inthe presence of p-toluenesulphonic acid. The preferred ester reactant isthe methyl ester. After the completion of the reaction, the solvent maythen be removed leaving the desired product as a residue.

Accordingly, the present invention provides a process for thepreparation of a compound of the general formulae I, II, III or IV aboveby any of the processes described above.

The starting materials of the formula HO-R⁵ wherein R⁵ is as hereinabovedefined may be prepared from the requisite alditol (polyhydroxyalcohol)and an appropriate aldehyde or ketone in the following manner:

The selected ketone or aldehyde and the alditol are brought together ina molar ratio in excess of 2:1 wherein it is anticipated that one dioxoring will be formed, or 4:1 wherein it is expected two dioxo rings willbe formed, and in the presence of a small amount of each of coppersulphate and concentrated sulfuric acid and the mixture is stirred,conveniently at room temperature, for from about 5 to about 24 hours oruntil the reaction is complete. The aldehyde or ketone is preferablyused in substantial excess; the aldehyde or ketone, for example, may beused in a sufficient excess so as to act as a reactant and as thereaction solvent. The mixture is then neutralized, for example, withaqueous ammonia. The copper sulphate and any other insoluble solids arefiltered off, after which the reaction mixture can be concentratedemploying conventional procedures. In one such procedure a rotaryevaporator can be employed. The crude residue can be purified employingconventional procedures. Most of the compounds can be recovered, forexample, by distillation in a khugelrohr apparatus, generally yieldingthe product as a oil.

Alternatively, the alditol may be reacted with the aldehyde or ketone inthe presence cf a suitable ion exchange resin, e.g. "DOWEX 50X8-400"(DOWEX is a Trade Mark of The Dow Chemical Company).

Suitable ketones for condensation with the alditol include acetone ordiisopropylketone or other ketones of the structure: ##STR8## wherein R¹and R² are as defined above.

Suitable aldehydes are formaldehyde, acetaldehyde, butyraldehyde,benzaldehyde, and chloral.

When the alditol derivative has two free hydroxyl groups (compounds offormulae C or E), either mono or bis addition of the trichlopyr (or itsderivative) is possible. By adding the trichlopyr (or its derivative)reactant to the alditol derivative. reactant, rather than the reverse,and controlling the amount of the reactant added to the stoichiometricamount, it is possible to arrange for substantially 1:1 addition, andthereby to prepare the compounds of the invention of formula III,wherein R⁴ is CH₂ OH. Further addition gives the bis-substituted product(where R⁴ is the group of formula A).

The compounds of the invention may be isolated from the reaction mixtureby customary processes, for example, by distilling off the solvent usedat normal or reduced pressure, by precipitation with water or byextraction. Generally, a higher degree of purity can be obtained bypurification by conventional column-chromatography or flashchromatography, or recrystallization of the product if a solid.

The compounds according to the invention are generally a yellowish gumin character, but some are non-crystalline solids, and some arecrystalline solids that are insoluble in water, and to a limited extent,in aliphatic hydrocarbons, such as, for example, petroleum ether,hexane, pentane and cyclohexane; and readily soluble in halogenatedhydrocarbons, such as, for example, chloroform, methylene chloride andcarbon tetrachloride, aromatic hydrocarbons, such as, for example,benzene, toluene and xylene, ethers, such as, for example, diethylether, tetrahydrofuran and dioxan, carboxylic acid nitriles, such as,for example, acetonitrile, ketones, such as, for example, acetone,alcohols, such as, for example, methanol and ethanol, carboxylic acidamides, such as, for example, dimethylformamide, and sulphoxides, suchas, for example. dimethyl sulphoxide.

During the synthesis, the active compounds are generally obtained as aracemic mixture and can be separated into the optical isomers utilizingknown procedures, for example, fractional crystallization can beemployed if the compound is a solid, or using a chiral chromatographiccolumn or by reacting with a resolving agent such as an alkaloid such asbrucine.

Synthesis of the optically pure compounds in accordance with theinvention may be carried out by using an optically unambiguous D or Lalditol as the starting material in making the alditol derivative.

The optical isomers, or enantiomers, of the compounds of the inventionexhibit differing biological activity, although neither the D or L formconsistently has the greater herbicidal action nor marked difference inselectivity and weed spectrum. The activity of the different isomer canbe easily observed.

The starting materials for the preparation of the compounds of theinvention are all known compounds and can be obtained commercially ormanufactured according to known procedures.

The compounds of the invention may be used alone or in a mixture withone another or the compounds can be employed along with other activesubstances, such as, for example, defoliants, plant protecting agentsand/or pesticides depending on the desired purpose.

The specific compound or mixture of compounds of the present inventionto be employed are not the same for all weeds and all crop plants, andare dependent on the specific weed species to be controlled and thespecific crop plant present.

If a broadening of the spectrum of action is intended, other biocidesmay also be employed. Examples of suitable herbicidally active mixingpartners are carbamic acid derivatives such as phenmedipham, triallate,diallate, and vernolate; dinitrophenol derivatives such as dinoseb anddinoseb acetate; chlorinated aliphatic acids such as trichloroaceticacid and dalapon; amides such as diphenamid andN,N-diallyl-2,2-chloroacetamide: dipyridilium compounds such as paraquatand diquat; anilides such as propanil, solan, monalide, propachlor,2-chloro-2', 6'-diethyl-N-methoxymethylacetanilide: nitriles such asdichlobenil and ioxynil; urea derivatives such as linuron, chloroxuron,monolinuron, fluometuron and diuron: triazine derivatives such assimazine, atrazine, ametryn, prometryn, desmetryn, methoprotryn,cyanazine and terbumeton; uracil derivatives such as lenacil andbromacil: growth-promoting preparations such as (2,4,5-trichlorophenoxy)acetic acid, 4-(4-chloro-2-methylphenoxy) butyric acid,2,3,6-trichlorobenzoic acid, 2-(4-chloro-2-methylphenoxy) propanoic acidand 3,6-dichloro-2-methoxybenzoic acid; aryloxy phenoxy postemergencegrass killers, such as haloxyfop; pyridine derivatives such as picloram,clopyralid and fluoroxypyr; and other preparations such as flurecol,3,4-dichloropropionanilide, trifluralin, bensulide, bifenox, bentazone,pyriate and glyphosate.

Particularly suitable mixing partners are the following: propanil,dichlobenil, ioxynil, diuron, atrazine, cyanazine, bromacil,(2,4,5-trichlorophenoxy) acetic acid, 2,3,6-trichlorobenzoic acid,2-(4-chloro2-methylphenoxy) propanoic acid,3,6-dichloro-2-methoxybenzoic acid, picloram, clopyralid, fluoroxypyr,bentazone, pyridate and glyphosate.

Surprisingly, mixtures, according to the invention, exhibit aconsiderably increased action against weeds with little, if any, damageto the cereal grains treated therewith. Used together with compounds ofthe invention, the herbicidal action of the mixing partners mentioned issuch that, under difficult conditions, such as application in highquantities, they have no specific damaging effect on cereal grains whileat the same time their spectrum of action against the weed type isbroadened.

The ratio of the components in the mixtures according to the inventionis preferably approximately from 1:10 to 10:1 more especially from 1:3to 3:1 by weight.

The exact dosage to be employed is not the same for all plants with allcompounds and is dependent upon the plant species and the stage ofgrowth at which treatment is made, and climatic conditions such astemperature, wind, and especially rainfall.

Preferred application quantities for selective weed control range from0.5 to 5.0 kg/ha for the mixing partners listed and from 0.2 to 2 kg/hafor the compounds in accordance with the invention.

It is also advantageous to apply from 0.25 to 5.0 kg/ha of a suitablesurface-active substance and other agents that intensify action, forexample, nonphytotoxic oils.

Advantageously, the active agents, materials or substances according tothe invention or mixtures thereof are used in the form of preparations,for example, powders, strewable agents, granulates, solutions, emulsionsor suspensions, with the addition of liquid and/or solid carriers ordiluents and, if desired, wetting agents, adhesion-promoting agents,emulsifiers and/or dispersing agents, but preferably in the form ofemulsion and emulsifiable concentrates.

Accordingly, the present invention provides a herbicidal preparationwhich comprises at least one compound of the general formulae I, II, IIIor IV, or a mixture thereof, and a suitable liquid or solid carrier.

Suitable liquid carriers are, for example, water, aliphatic and aromatichydrocarbons, such as, for example, toluene and xylene, cyclohexanone,isophorone, dimethyl sulphoxide, dimethylformamide, and also mineral oilfractions.

Suitable solid carriers are, for example, mineral earths, for example,tonsil, silica gel, talcum, kaolin, attaclay, limestone, silica acid andvegetable products, for example, meals.

The preparation advantageously includes a surface-active substance(s).Suitable surface-active substances are, for example, calciumligninsulphonate, polyoxyethylene alkylphenol ethers,naphthalenesulphonic acids and salts thereof, phenolsulphonic acids andsalts thereof, formaldehyde condensates, fatty alcohol sulphates andsubstituted benzenesulphonic acids and salts thereof.

The proportion of the active substances in the various preparations mayvary within wide limits. For example, the preparations may contain from5 to 95 percent by weight of active substances, from 95 to 5 percent byweight of liquid or solid carriers and, if desired, up to 20 percent byweight of surface-active substances.

The present invention also provides a process of combating weeds, whichcomprises applying postemergently to said weeds, a compound or mixtureof compounds in accordance with the invention; and if desired, otheractive substances, especially an additional herbicide from the list ofmixing partners given hereinabove.

Suitably, the compounds are in the form of a herbicidal preparationcomprising the active ingredient and carrier and herbicide mixingpartner when one is used.

The compounds or preparations may be applied in customary manner, forexample, using water as a carrier. The final preparations may beemployed in quantities of spraying liquor of from 100 to 1000 liters/ha.It is possible to use the active agents in the so-called Low Volume andUltra Low Volume processes, and also to apply them in the form ofsocalled micro-granules.

The following examples illustrate the present invention and the mannerin which it can be practiced but as such, are not to be construed aslimitations upon the overall scope of the same.

EXAMPLE 1 A. 2.3:4,5-Di-isopropylidene-L-arabitol

A mixture of L-(-)-arabitol (30 g, 0.197 mole) anhydrous copper sulphate(24 g), concentrated sulphuric acid (4 ml) and acetone (600 ml) werestirred well at room temperature for 18 hours, then neutralized withconcentrated aqueous ammonia and filtered. The solution was concentratedusing a rotary evaporator to yield a yellow oil as residue. The yellowoil was distilled on a khugelrohr apparatus (110° C.) to yield the titlecompound (35.5 g, 78 percent) as a colorless oil.

    ______________________________________                                        Elemental Analysis                                                                               C    H                                                     ______________________________________                                        Calculated for C.sub.11 H.sub.20 O.sub.5                                                           56.88  8.68                                              Found:               56.87  8.52                                              ______________________________________                                    

B. 3,5,6-Trichloro-2-pyridyloxyacetyl Chloride (Acid Chloride ofTriclopyr)

3,5,6-Trichloro-2-pyridyloxyacetic acid (20 g, 0.078 mole was stirredwith toluene (46.5 ml). Thionyl chloride (26 ml) was added dropwise tothe well-stirred mixture over 15 minutes. The mixture was then heatedunder reflux (70° C.) for 3 hours. The effluent gases (SO₂ +HCl) wereabsorbed into aqueous 5N sodium hydroxide. The cooled reaction mixturewas filtered and evaporated to yield the title compound (20.9 g, 98percent) as a thick dark brown oil.

C.(3,5,6-Trichloro-2-pyridyloxyacetyl)-2,3:4,5-di-O-(isopropylidene)-L-arabitol(Compound XVI)

2,3:4,5-Di-O-isopropylidene-L-arabitol (6.0 g, 0.026 mole) was dissolvedin acetonitrile (30 ml) and triethylamine (3 g) added.3,5,6-Trichloro-2-pyridyloxyacetyl chloride (7.1 g, 0.026 mole, inacetonitrile (20 ml) was added dropwise with stirring over 15-20minutes. The mixture was stirred for an additional 3 hours, and thecompletion of the reaction was determined employing thin layerchromatography (TLC) of small samples of the reaction mixture.

On cooling, the solid precipitate was removed by filtration, and thefiltrate concentrated employing a rotary evaporator. The oily residuewas taken up in dichloromethane (100 mls) and washed thoroughly withwater to remove any triethylamine hydrochloride remaining. After dryingwith sodium sulphate, evaporation of the dichloromethane layer gave athick dark brown oil as a crude product.

This was eluted over a neutral alumina column using benzene as thesolvent to yield the title compound (6.9 g, 57 percent) as a pale yellowviscous gum.

    ______________________________________                                        Elemental Analysis                                                                             C      H      N                                              ______________________________________                                        Calculated for C.sub.18 H.sub.22 Cl.sub.3 NO.sub.7 :                                             45.93    4.71   2.98                                       Found:             46.10    4.55   2.98                                       ______________________________________                                    

EXAMPLE 2 A. 2.3:4.5-Di-O-isopropylidene-D-arabitol

A mixture of D-(+)-arabitol (30 g, 0.177 mole) anhydrous copper sulphate(24 g), concentrated sulphuric acid (4 ml), and acetone (600 ml) werestirred well at room temperature for 18 hours, then neutralized withconcentrated aqueous ammonia and filtered. The solution was concentratedusing a rotary evaporator to yield a blue-green oil as the residue.

The blue-green oil was distilled on a khugelrohr apparatus (110° C.) toyield the title compound (38.0 g, 83 percent) as a colorless oil.

B. 3,5,6-Trichloro-2-pyridyloxyacetyl-2,3:4,5-di-O-(isopropylidene)-D-arabitol (Compound V)

The procedure of Example 1-C was repeated except there was used theabove described 2,3:4,5-di-O- isopropylidene-L-arabitol in place of theD compound.

The title compound was obtained (8.3 g, 68 percent) as a pale yellowviscous gum.

    ______________________________________                                        Elemental Analysis                                                                             C      H      N                                              ______________________________________                                        Calculated for C.sub.18 H.sub.22 Cl.sub.3 NO.sub.7 :                                             45.93    4.71   2.98                                       Found:             46.46    4.72   2.80                                       ______________________________________                                    

EXAMPLE 33,5,6-Trichloro-2-pyridyloxyacetyl-1,2-(isopropylidene)-glycerolCompound VI)

N,N'-carbonyldiimidazole (8.75 g, 0.054 mole) was added to3,5,6-trichloro-2-pyridyloxyacetic acid (13.8 g, 0.054 mole) in drytetrahydrofuran (120 ml) at room temperature with constant stirring.When evolution of carbon dioxide ceased, the mixture was treated with1,2-isopropylidene glycerol (7.1 g, 0.054 mole) and stirred for anadditional hour and then allowed to stand overnight. The progress of thereaction was followed by TLC.

The solid precipitate was removed by filtration and the filtrateconcentrated on the rotary evaporator. The oily residue was taken up indichloromethane (100 ml) and washed thoroughly with water. After dryingwith sodium sulphate, evaporation gave a pale, brown oil. This waseluted with benzene over a neutral alumina column to yield the productas a pale yellow oil (8.3 g, 41.5 percent).

    ______________________________________                                        Elemental Analysis                                                                             C      H      N                                              ______________________________________                                        Calculated for C.sub.13 H.sub.22 Cl.sub.3 NO.sub.7 :                                             42.13    3.81   3.78                                       Found:             42.07    3.75   3.66                                       ______________________________________                                    

After a short period of standing, the oil crystallized out.Recrystallization from hexane yielded the title compound (6.9 g, 34.5percent) as a white crystalline solid, m.p. 73° -74° C.

EXAMPLE 41-(3,5,6-Trichloro-2-pyridyloxyacetyl)-2,4-(methylene)-adonitol(Compound VIII)

N,N'Carbonyloiimidazole (3.47 g, 0.0195 mole) was added to3,5,6-trichloro-2-pyridyloxyacetic acid (5.0 g, 0.0195 mole) in drytetrahydrofuran (70 ml) at room temperature with constant stirring. Whenevolution of carbon dioxide ceased, the mixture was added dropwise to asolution of 2,4-methylene adonitol (3.2 g, 0.0195 mole) in drytetrahydrofuran (70 ml). After stirring for an hour, the reaction wasallowed to stand overnight.

The solid precipitate was removed by filtration, and the filtrateconcentrated on a rotary evaporator. The oil residue was taken up indichloromethane (100 ml) and washed thoroughly with water. After dryingwith sodium sulphate, evaporation gave a gum. This product was elutedwith ethyl acetate and hexane mixtures (starting with 1:4 and endingwith 100 percent ethyl acetate) over a silica column to yield theproduct as a white solid, m.p. 123.6° C. (7.0 g, 79.5 percent).

    ______________________________________                                        Elemental Analysis                                                                             C      H      N                                              ______________________________________                                        Calculated for C.sub.13 H.sub.22 Cl.sub.3 NO.sub.7 :                                             38.78    3.51   3.48                                       Found:             38.99    3.47   3.54                                       ______________________________________                                    

EXAMPLES 5 to 13

The following compounds were prepared in an analogous manner:

    ______________________________________                                        Example                      M. pt. if                                        No.     Name of Compound     solid (°C.)                               ______________________________________                                        5       (3,5,6-trichloro-2-pyridyloxy-                                                                     oil                                                      acetyl)-2,3:4,5-di-O-(isopropyl-                                              idene)xylitol; (Compound VII)                                         6       (3,5,6-trichloro-2-pyridyloxy-                                                                      97.5                                                    acetyl)-1,3-(benzylidene)-                                            glycerol; (Compound X)                                                        7       (3,5,6-trichloro-2-pyridyloxy-                                                                     oil                                                      acetyl)-1,2-(benzylidene)-                                                    glycerol; (Compound XI)                                               8       (3,5,6-trichloro-2-pyridyloxy-                                                                     120.5                                                    acetyl)-1,2-(methylene)-glycerol;                                             (Compound XII)                                                        9       (3,5,6-trichloro-2-pyridyloxy-                                                                     126.2                                                    acetyl)-1,3:2,4-di-O-(methylene)-                                             adonitol; (Compound XIII)                                             10      (3,5,6-trichloro-2-pyridyloxy-                                                                     oil                                                      acetyl)-1,2-(butylidene)-                                                     glycerol; (Compound XIV)                                              11      (3,5,6-trichloro-2-pyridyloxy-                                                                     oil                                                      acetyl)-1,2-(cyclohexylidene)-                                                glycerol; (Compound XV)                                               12      (3,5,6-trichloro-2-pyridyloxy-                                                                     oil                                                      acetyl)-2,3:4,5-di-O-(isopropyl-                                              idene)-L-arabitol; (Compound XVI)                                     13      bis-[1,4-(3,5,6-trichloro-2-                                                                       oil                                                      pyridyloxyacetyl)]-2,3-(iso-                                                  propylidene)-threitol;                                                        Compound XVII)                                                        ______________________________________                                    

FORMULATION EXAMPLES

The following Examples A to C are illustrations of typical formulationsin which the compounds of the invention may be utilized.

A. Wettable Powder

(a)

40 percent by weight of active substance

25 percent by weight of clay minerals

20 percent by weight of colloidal silica

10 percent by weight of cellulose pitch

5 percent by weight of surfactant based on a mixture of the calcium saltof lignin-sulphonic acid and alkylphenol polyglycol ethers

(b)

25 percent by weight of active substance

60 percent by weight of kaolin

10 percent by weight of colloidal silica

5 percent by weight of surfactant based on the sodium salt ofN-methyl-N-oleyltaurine and the calcium salt of lignin-sulphonic acid

(c)

10 percent by weight of active substance

60 percent by weight of clay minerals

15 percent by weight of cellulose pitch

10 percent by weight of surfactants based on the sodium salt ofN-methyl-N-oleyltaurine and the calcium salt of lignin-sulphonic acid

B. Paste

45 percent by weight of active substance

5 percent by weight of sodium aluminum silicate

15 percent by weight of cetyl polyglycol ether with 8 moles of ethyleneoxide

2 percent by weight of spindle oil

10 percent by weight of polyethylene glycol

23 percent by weight of water

C. Emulsion Concentrate

(a)

25 percent by weight of active substance

15 percent by weight of cyclohexanone

55 percent by weight of xylene

5 percent by weight of a mixture of nonylphenyl polyoxyethylenes orcalcium dodecylbenzenesulphonate

(b)

10 percent by weight of active substance

6 percent by weight of cyclohexanone

36 percent by weight of xylene

12 percent by weight of a mixture of nonylphenyl polyoxyethylenes orcalcium dodecylbenzenesulphonate

36 percent by weight of mineral oil having a high paraffin content.

The following examples illustrate possible uses of the compounds andmixtures according to the invention which were used in the form of theabove-mentioned preparations.

EXAMPLE 14

Glasshouse tests were carried out to determine the herbicidal efficacyof a postemergence application of the esters of triclopyr prepared inExamples 1 to 13.

The esters of triclopyr in accordance with the invention were preparedas described hereinabove by coupling the corresponding free acid withthe appropriate alditol derivative as described in Examples 1 to 4 inthe presence of N,N'-carbonyldiimidazole. The chiral D- and L-esterherbicides were produced by using the corresponding D- and L-arabitolacetonides prepared from D- and L-alcohols. The esters were purified bycolumn chromatography on neutral alumina.

The new compounds were characterized by Infrared Spectroscopy, NuclearMagnetic Resonance Spectroscopy and Elemental Analysis and had thestructures given above.

METHOD

All plants were cultivated in the glasshouse, to a true 2-4 leaf stage,in a mixture of 70 percent peat, 20 percent sharp sand and 10 percentpotting grit. Then they were placed in a cooler area to harden off, attemperatures ranging from 5° C. at night to 15° C. during the day.

Concentrates of the respective new compounds were made up as aqueouscompositions in water utilizing 25 percent acetone and 0.25 percent of asurfactant (Triton X-100), to disperse the active ingredients (TRITONX-100 is a Trade Mark).

The concentrates were then further diluted with water containing 0.25percent of Triton X-100, to produce sprayable formulations of thedesired concentration.

All formulations were applied to the plants using a MARDRIVE overheadsprayer set at 30 psi, delivering 300 l/ha. Plants were returned to theglasshouse after treatment and were subjected to temperatures rangingbetween 15° C. at night to 20° C. during the day. The compounds wereapplied at rates of 960, 480 and 240 grams active ingredient (calculatedas trichlopyr free acid) per hectare (g ai/ha).

Application of the formulations was made to the following plantspostemergently.

    ______________________________________                                        Weeds:              Crops:                                                    ______________________________________                                        Cleaver (Galium aparine)                                                                          Barley (Golden Promise)                                   Fat hen (Chenopodium album)                                                                       Wheat (Norman)                                            Red Dead nettle                                                               (Lamium purpureum)                                                            Pansy (Viola arvensis)                                                        Assessments                                                                   A 0-5 scale was used to assess all tests:                                     0 = Normal healthy plants                                                     5 = Dead                                                                      Efficacy results at indicated times and application                           rates are summarized in Table 1.                                              ______________________________________                                    

                                      TABLE 1                                     __________________________________________________________________________    Activity Assessment of Arabitol Derivative Esters                                      Cleaver                                                                             Red Dead Nettle                                                                        Pansy Fat hen                                                                             Wheat Barley                              Compound                                                                            Rate                                                                             Days  Days     Days  Days  Days  Days                                No.   g/ha                                                                             4 13                                                                              19                                                                              4  13 19 4 13                                                                              19                                                                              4 13                                                                              19                                                                              4 13                                                                              19                                                                              4 13                                                                              19                              __________________________________________________________________________    V     960                                                                              3 3 1 3  4  4  3 3 3 4 4 4 0 0 --                                                                              0 0 --                                    480                                                                              3 2 0 3  3  4  3 3 3 4 4 4 0 0 --                                                                              0 0  --                                   240                                                                              2 2 0 2  3  3  3 3 2 4 4 4 0 0 --                                                                              0 0  --                             VI    960                                                                              2 0 0 2  2  4  1 3 2 4 4 4 0 0 0 0 0  0                                    480                                                                              1 0 0 0  1  2  1 2 1 4 4 4 0 0 0 0 0  0                                    240                                                                              0 0 0 0  1  2  0 2 0 4 4 4 0 0 0 0 0  0                              VII   960                                                                              0 0 0 0  2  3  1 1 0 3 4 4 0 0 0 0 0  0                                    480                                                                              0 0 0 0  2  2  1 1 0 3 3 4 0 0 0 0 0  0                                    240                                                                              0 0 0 0  2  2  1 1 0 2 3 4 0 0 0 0 0  0                              VIII  960                                                                              1 2 2 1  2  2  2 2 2 3 4 4 0 0 0 2 1  1                                    480                                                                              --                                                                              --                                                                              --                                                                              -- -- -- 2 2 1 3 4 3 --                                                                              --                                                                              --                                                                              2 1  1                                    240                                                                              --                                                                              --                                                                              --                                                                              -- -- -- 2 2 1 2 3 3 --                                                                              --                                                                              --                                                                              2 1  1                              IX    960                                                                              0 0 0 0  0  0  1 2 2 3 4 3 0 0 0 2 1  0                                    480                                                                              --                                                                              --                                                                              --                                                                              -- -- -- 1 1 1 2 3 2 --                                                                              --                                                                              --                                                                              1 1  0                                    240                                                                              --                                                                              --                                                                              --                                                                              -- -- -- 0 0 0 2 3 2 --                                                                              --                                                                              --                                                                              1 1  0                              X     960                                                                              2 2 3 1  0  1  0 1 1 2 3 3 0 0 0 2 0  0                                    480                                                                              --                                                                              --                                                                              --                                                                              1  0  0  0 1 0 2 3 3 --                                                                              --                                                                              --                                                                              1 0  0                                    240                                                                              --                                                                              --                                                                              --                                                                              1  0  0  0 1 0 2 3 3 --                                                                              --                                                                              --                                                                              1 0  0                              XI    960                                                                              2 3 4 2  3  3  3 2 3 3 3 3 0 0 0 3 3  3                                    480                                                                              --                                                                              --                                                                              --                                                                              -- -- -- --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              -- --                                   240                                                                              --                                                                              --                                                                              --                                                                              -- -- -- --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              --                                                                              -- --                             XII   960                                                                              2 0 0 1  3  3  1 3 2 2 3 3 0 0 0 0 1  1                                    480                                                                              2 0 0 0  2  2  1 1 0 2 3 3 0 0 0 0 0  0                                    240                                                                              1 0 0 0  2  2  1 1 0 2 3 3 0 0 0 0 0  0                              XIII  960                                                                              1 1 2 0  0  0  1 0 1 3 3 2 0 0 0 1 0  0                                    480                                                                              --                                                                              --                                                                              --                                                                              -- -- -- 1 0 0 2 2 2 --                                                                              --                                                                              --                                                                              1 0  0                                    240                                                                              --                                                                              --                                                                              --                                                                              -- -- -- 0 0 0 2 2 0 --                                                                              --                                                                              --                                                                              0 0  0                              XIV   960                                                                              2 3 4 -- -- -- 3 2 4 3 3 3 0 0 0 3 3  4                                     80                                                                              1 2 2 -- -- -- 3 2 4 3 3 3 0 0 0 2 3  3                              XV    960                                                                              2 3 4 -- -- -- 3 3 4 3 4 4 0 0 0 3 3  3                                    480                                                                              2 3 3 -- -- -- 3 3 4 3 3 3 0 0 0 3 3  3                              XVI   960                                                                              3 3 2 2  4  4  3 3 4 4 4 5 0 0 --                                                                              0 0  --                                   480                                                                              2 3 2 3  4  4  3 2 2 4 4 5 0 0 --                                                                              0 0  --                                   240                                                                              2 2 0 3  3  3  2 2 0 4 4 5 0 0 --                                                                              0 0  --                             XVII  960                                                                              1 1 1 -- -- -- 2 0 1 3 3 3 0 0 0 2 2  2                                    480                                                                              1 0 1 -- -- -- 2 0 1 3 3 3 0 0 0 2 2  1                              Control                                                                             -- 0 0 0 0  0  0  0 0 0 0 0 0 0 0 0 0 0  0                              __________________________________________________________________________     Assessment Scale 0-5: 0 = Normal healthy plants; 5 = dead                

EXAMPLE 15

Various of the alditol ester according to the invention were tested fortheir volatile vapor effects on adjacent sensitive crops.

A wind tunnel was prepared using a glasshouse constructed of transparentrigid sheets secured to a tubular aluminum frame 0.43 m high, 0.84 mwide and 3.05 m in length.

An airflow was introduced into one end of the tunnel using a Secomak(Model 573) fan giving an airflow of 3/4 M.P.H. from a manifold andvented to the atmosphere at the opposite end of the tunnel.

Test compounds were sprayed over a field target containing plantsrepresentative of plants to be treated in the field at normal fieldrates and volumes (substantially 960 g/ha calculated as trichlopyr freeacid). The target was allowed to dry and was then introduced into theupwind end of the tunnel. Air was passed over the target for a period of24 hours and vented to the atmosphere outside the glasshouse.

Various sensitive plants (cotton, barley, pinto beans, and rape) weregrown at varying distances downwind of the target over the 24 hourperiod.

After 24 hours the sensitive plants were removed from the tunnel andgrown on a glasshouse bench for a further period of 14 days.

Plants exposed at distances of 0, 1, 2, 3, 4, 5, 6 and 7 feet (0, 0.3,0.6, 0.9, 1.2, 1.5, 1.8 and 2.1 meters) from the target were assessedvisually immediately after removal from the tunnel, on a scale of 0 to5, where 0=normal healthy plants, and 5=dead.

The results are shown in Table 2. Further observation of the plants overthe 14-day period after removal from the tunnel showed no significantchange in their score from those obtained immediately after theirremoval from the tunnel.

                                      TABLE 2                                     __________________________________________________________________________    Volatility Assessments of Arabitol Derivative Esters                                Cotton   Barley   Pinto Beans                                                                            Rape                                         Compound                                                                            Distance in Feet                                                                       Distance in Feet                                                                       Distance in Feet                                                                       Distance in Feet                             No.   0 1 2 3 4 5 6 7                                                                        0 1 2 3 4 5 6 7                                                                        0 1 2 3 4 5 6 7                                                                        0 1 2 3 4 5 6 7                              __________________________________________________________________________    VI    0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                              VII   0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                              XII   0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                              XVI   0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                              Control                                                                             0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                                                                        0 0 0 0 0 0 0 0                              __________________________________________________________________________     Assessment Scale 0-5: 0 = Normal healthy plants; 5 = dead                

EXAMPLE 16

Representative compositions of the present invention were evaluated todetermine their selectivity to wheat in postemergent operations.

Aqueous dispersions were prepared by admixing predetermined amounts ofone of the hereinafter set forth compounds, dissolved in a predeterminedamount of an inert solvent with a predetermined quantity of water and apredetermined amount of a surfactant to give aqueous dispersions of oneof the compounds as the sole toxicant.

Plant seeds of predetermined plant species were planted in beds of goodagricultural soil and grown in a greenhouse. After the plants hademerged and had grown to the four leaf stage, the plants were sprayed torunoff with one of the above-prepared compositions at treating rates.Other beds of the plants were sprayed with a water-surfactant mixture,containing no active compound, to serve as controls. After treatment,the beds were maintained for two weeks under greenhouse conditionsconducive for good plant growth. At the end of this period, the bedswere examined to determine the amount of kill and control. The specificplant species, test compounds and the percent postemergent control areset forth below in Table 3.

                                      TABLE 3                                     __________________________________________________________________________    Wheat Selectivity of Arabitol Derivative Esters                                           Percent Kill and Control of Indicated Plant Species                           at Indicated Treating Rate                                        Compound                                                                            Treating   Velvet                                                                             Morning                                                                            Jimson                                             No.   Rate g/ha                                                                           Wheat                                                                              Leaf Glory                                                                              Weed                                                                              Cocklebur                                      __________________________________________________________________________    V     1290  0    40   100  NT  100                                                   640  0    40   100  100 70                                             VI    1290  0    75   100  NT  100                                                   640  0    55   100  95  95                                             VII   1290  0    80   100  95  NT                                                    640  0    80   100  85  NT                                             VIII  1290  20   60   100  98  98                                                    640  0    70   100  40  90                                             X     1290  20   100  100  100 98                                                    640  0    100  100  100 95                                             XII   1290  0    NT   100  90  NT                                                    640  0    70   100  50  NT                                             XIII  1290  35   60   100  100 90                                                    640  20   60   100  90  80                                             Control                                                                             --    0     0    0    0   0                                             __________________________________________________________________________

EXAMPLE 17

Representative compositions of the present invention were evaluated todetermine their selectivity to rice in postemergent operations.

Aqueous dispersions were prepared by admixing predetermined amounts ofone of the hereinafter set forth compounds, dissolved in a predeterminedamount of an inert solvent with a predetermined quantity of water and apredetermined amount of a surfactant to give aqueous dispersions of oneof the compounds as the sole toxicant.

Plant seeds of predetermined plant species were planted in beds of goodagricultural soil and grown in a greenhouse. After the plants hademerged and had grown to the four leaf stage, the plants were sprayed torunoff with one of the above-prepared compositions at treating rates.Other beds of the plants were sprayed with a water-surfactant mixture,containing no active compound, to serve as controls. After treatment,the beds were maintained for two weeks under greenhouse conditionsconducive for good plant growth. At the end of this period, the bedswere examined to determine the amount of kill and control. The specificplant species, test compounds and the percent postemergent control areset forth below in Table 4.

                  TABLE 4                                                         ______________________________________                                        Rice Selectivity of Arabitol Derivative Esters                                                Percent Kill and Control of Indicated Plant                   Com-   Treating Species at Indicated Treating Rate                            pound  Rate            Velvet                                                                              Morning                                                                              Jimson                                                                              Cockle-                             No.    g/ha     Rice   Leaf  Glory  Weed  bur                                 ______________________________________                                        VI     1290     35     75    100    NT    100                                         640     0      55    100    95    95                                  VII    1290     0      80    100    95    NT                                          640     0      80    100    85    NT                                  VIII   1290     40     60    100    98    98                                          640     0      70    100    40    90                                  XII    1290     30     NT    100    90    NT                                          640     0      70    100    50    NT                                  XIII   1290     30     60    100    100   90                                          640     0      60    100    90    80                                  Control                                                                              --       0       0     0      0     0                                  ______________________________________                                    

We claim:
 1. A compound corresponding to the general formula ##STR9## wherein Z represents ##STR10## R¹ and R² are each independently any sterically compatible combination of H, a C₁ -D₆ straight chain or branched alkyl group, a C₃ -C₆ cycloalkyl group, or phenyl; orR¹ and R² taken together represent a divalent polymethylene group --CH₂ --n, thereby forming a carbocyclic ring having n+1 carbon atoms wherein n is 3, 4, 5 or
 6. 2. The compound as defined in claim 1 which is (3,5,6-trichloro-2-pyridyloxyacetyl) 1,3:2,4-di-O--(methylene)-adonitol.
 3. A herbicidal composition which contains as the active component an alditol derivative ester of triclopyr in intimate admixture with an inert carrier therefor and said active component is a compound corresponding to one of the general formula ##STR11## wherein Z represents ##STR12## R¹ and R² are each independently any sterically compatible combination of H, a C₁ -C₆ straight chain or branched alkyl group, a C₃ -C₆ cycloalkyl group, or phenyl; orR¹ and R² taken together represent a divalent polymethylene group --CH₂ --n, thereby forming a carbocyclic ring having n+1 carbon atoms wherein n is 3, 4, 5 or
 6. 4. A composition as defined in claim 3 wherein R¹ and R² are each independently H, methyl or phenyl.
 5. A composition as defined in claim 4 wherein R¹ and R² are different.
 6. A composition as defined in claim 4 wherein R¹ and R² are the same.
 7. A composition as defined in claim 6 wherein R¹ and R² are each hydrogen or methyl.
 8. A composition as defined in claim 7 wherein R¹ and R² are each hydrogen.
 9. A composition as defined in claim 6 wherein R¹ and R² are each methyl.
 10. The composition as defined in claim 8 wherein the active component is (3,5,6-trichloro-2--pyridyloxyacetyl) 1,3:2,4-di-O-(methylene)-adonitol.
 11. A method for the postemergent kill and control of weeds which comprises applying to said weeds a herbicidally effective amount of a composition containing as the active component an alditol derivative ester of triclopyr in intimate admixture with an inert carrier therefor and said active component is a compound corresponding to one of the general formula ##STR13## wherein Z represents ##STR14## R¹ and R² are each independently any sterically compatible combination of H, a C₁ -C₆ straight chain or branched alkyl group, a C₃ -C₆ cycloalkyl group, or phenyl; orR¹ and R² taken together represent a divalent polymethylene group --CH₂ --n, thereby forming a carbocyclic ring having n+1 carbon atoms wherein n is 3, 4, 5 or
 6. 12. A method as defined in claim 11 wherein R¹ and R² are each independently H, methyl or phenyl.
 13. A method as defined in claim 11 wherein R¹ and R² are different.
 14. A method as defined in claim 11 wherein R¹ and R² are the same.
 15. A method as defined in claim 14 wherein R¹ and R² are each hydrogen or methyl.
 16. A method as defined in claim 15 wherein R¹ and R² are each hydrogen.
 17. A method as defined in claim 14 wherein R¹ and R² are each methyl.
 18. The method as defined in claim 16 wherein the active component is (3,5,6-trichloro-2-pyridyloxyacetyl) 1,3:2,4-di-O-(methylene)-adonitol. 